Field of the Invention
The present invention relates to a vibration reduction apparatus, a lithography apparatus, and a method of manufacturing an article.
Description of the Related Art
In a lithography apparatus for forming a pattern on a substrate, the vibration transferred from the base to the main body of the lithography apparatus is a cause of degradation in overlay precision and transferring precision. For this reason, the lithography apparatus uses a vibration reduction apparatus for reducing the vibration of a target object such as a base plate on which the main body of the lithography apparatus is mounted.
Japanese Patent Laid-Open No. 2013-190070 has proposed a vibration reduction apparatus which reduces the vibration of a target object supported on the base by using an elastic member (for example, an air spring). The vibration reduction apparatus disclosed in Japanese Patent Laid-Open No. 2013-190070 includes an actuator which drives the target object and a reference system having a reference object. It is possible to reduce the vibration of the target object by performing feedback control on the actuator so as to make the relative distance between the target object and the reference object of the reference system constant.
The reference system of the vibration reduction apparatus disclosed in Japanese Patent Laid-Open No. 2013-190070 includes the first object supported on the base, the second object supported on the first object, a detection unit which detects the distance between the first object and the second object, and a driving unit which drives the first object. In the reference system, it is possible to reduce the vibration of the second object serving as the reference object by performing feedback control on the driving unit so as to make the distance detected by the detection unit constant.
In such a reference system, assume a case in which an electrostatic capacitance sensor, an eddy current displacement sensor, or the like is used as the detection unit to detect the distance between the first object and the second object. In this case, if a cable line itself connected to the second object vibrates, the second object also vibrates in response to this, thus making it difficult to reduce the vibration of the target object.